An eyewitness tells the publication, “They were making out at Soho House. They were all over each other for a lot of the night.”

Michael Sheen. (Photo by Michael Buckner/Getty Images for UNICEF)

Silverman also attended Sheen’s 45th birthday party at Craig’s restaurant in Los Angeles last week along with Demi Moore, Sheen’s “Masters of Sex” co-star Lizzy Caplan, and his former partner Kate Beckinsale.

A source says, “Sarah and Michael came and left together. She drove. When they left, Sarah opened her trunk so Michael could put all of his gifts in and then they drove away.”

Sheen and Beckinsale split in 2003 after eight years together, while his relationship with actress Rachel McAdams came to an end in 2013.